Biobased Nanoemulsions: Concept, Formulation, and Applications

Abstract

Nanoemulsions are one of the growing technologies with applications in diverse areas such as drug delivery, food, cosmetics, pharmaceuticals, and material synthesis. Nanoemulsions are kinetically stable liquid-in-liquid dispersions, with a mean droplet size in the range of 20–200 nm. Other characteristics of nanoemulsions include optical clarity; good stability against separation, flocculation, and coalescence; a large surface area per unit volume; and tunable rheology. Because of their size, it is possible to improve absorption and bioavailability of functional compounds—qualities that are important for their utilization in many foods, beverages, and drug delivery systems. High- and low-energy methods are used to prepare nanoemulsions, including high-pressure homogenization, ultrasonication, the phase inversion temperature method, and the emulsion inversion point method, as well as recently developed approaches such as the bubble-bursting method. The stability of the formulation may be enhanced by control of factors such as the types and concentrations of the surfactant and cosurfactant, the type and content of the oil phase, the methods used, process variables, and additives. The research trends in nanoemulsions are biobased ones, which include the use of natural emulsifiers and oils such as lecithin, casein, β-lactoglobulin, polysaccharides, soybean oil, sesame oil, cottonseed oil, safflower oil, coconut oil, rice bran oil, and cinnamon oil. In this chapter, we summarize the state of the art of biobased nanoemulsions.